The production of oxirane compounds such as propylene oxide by the catalytic reaction of an olefin and an organic hydroperoxide is a process of great importance which is practiced on a large scale in the industrial world. U.S. Pat. No. 3,351,635 is the basic patent covering this process.
In one version of the process, an insoluble solid heterogenous catalyst is used; see, for example, U.S. Pat. No. 4,367,342. A disadvantage of the use of the heterogeneous catalysts, as contrasted with the use of soluble homogeneous catalyst systems, has been the tendency for the solid catalyst to deactivate over time resulting in a loss both of productivity and reaction selectivity. A potential advantage of the use of the heterogeneous catalysts would be decreased problems associated with the disposal of metal containing waste streams.
The problems of solid catalyst deactivation, especially as they relate to high volume continuous commercial processes, have been the subject of extensive studies. It has been found that the production of a hydroperoxide such as ethyl benzene hydroperoxide which can be used in the solid heterogeneous catalyzed epoxidation of olefin can be improved by an aqueous base treatment whereby the process shows greatly reduced deactivation of the solid catalyst. However, the aqueous stream resulting from such treatment presents its own disposal problems; the present invention provides a treatment to remove impurities from such aqueous streams.